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Warfarin


What does it do?

How do I take it?

Side Effects

What else should I know?

What does it do?

Warfarin is an "anticoagulant", which increases the amount of time it takes for your blood to clot. This helps to prevent blood clots from forming.  This is important if you have an irregular heart beat, have had a heart valve replaced or if you have had a clot before. 

Warfarin is very powerful in stopping your blood from clotting but you need to keep a very careful watch on how thin your blood is.  If it gets too thin, you can bleed very easily if you hurt yourself – sometimes even a very soft knock could cause a lot of bruising.  Of course if your blood isn't thin enough then you won't get the effect of reducing the time the blood takes to clot.  The test to check the thinness of your blood is called an INR test.  Your result should generally be between 2 and 3.

In Glasgow there will be a clinic near you where you can go for regular blood checks. This is called the Anticoagulant Clinic. The nurse or pharmacist there will tell you how often to attend the clinic and it's very important that you don't miss a visit. 

They will give you an information booklet about Warfarin.  It is important that you read the booklet and carry it with you.  It will tell you the important things you need to know about Warfarin. 

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How do I take it?

You should take Warfarin tablets by mouth once a day and it is important to take them at the same time every day (usually between 5 and 7 each evening). The number of tablets you take may change after you have had your blood checked at the anticoagulant clinic.

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Side Effects

If you are taking Warfarin you can occasionally have a problem with bleeding from your nose or gums and you will bruise much more easily.  Sometimes blood may appear in the urine or bowel motions.  If you notice any abnormal bruising or bleeding you must tell your doctor immediately. 

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What else should I know?

  • Always take the correct dose. 
  • Always carry your yellow Anticoagulant card (your Warfarin booklet) with you in case of an accident. 
  • Never miss a dose: If you forget to take a dose take it as soon as you remember the same day. Do not double your dose the next day. 
  • Always tell any Doctor, Dentist or Pharmacist you consult that you are taking Warfarin. 
  • Do not take any aspirin that has not been prescribed by your doctor. Many painkillers and cold & flu remedies you can buy also contain aspirin. Always tell your pharmacist you are taking Warfarin before you buy any medicines. 
  • Do not take any new medicines without checking with your GP, practice nurse, pharmacist or anticoagulant clinic first. Many common medicines, even those bought in supermarkets and health food shops can make Warfarin less effective (e.g. St Johns Wart). 
  • Always let your doctor, practice nurse or anticoagulant clinic know if you are going to stop taking any medicine – that might mean you need more or less Warfarin.
  • Keep to your normal diet; you may drink moderate amounts of alcohol, but avoid drinking large amounts regularly, or in a single session, as this can interfere with control of your treatment. 
  • If you believe you may be pregnant, see your GP as soon as possible. 
  • Inform your GP if you get a rash.

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